Lia nodded a yes - and once she got over the shock, he revealed her family had watched the entire show.

"She was very taken aback," he said. "She was overwhelmed."

Marshall told IE that the epic proposal came after weeks of planning and input from his family and colleagues - as well as a fair bit of lying.

Lia knew a proposal was just around the corner, so he told her he'd booked a special dinner for the weekend. Her sisters - who were in on the plan - suggested it might be the night he popped the question.

In fact, the firehouse proposal fell a day earlier, completely catching her off guard. And instead of booking the special dinner, he had actually organized an engagement party.

After such an impressive proposal, "I told her it's all downhill from here," he joked.

Marshall, who hopes they'll marry in the Fall, added that he's glad the special moment was caught on film.